Page:Graphic methods for presenting facts (1914).djvu/373

 *ting curves is to take one set of data and plot those data in several different ways, noticing the changes which the different scales selected give in the proportions of the chart. Just as the written or spoken English language may be used to make gross exaggerations, so charts and especially curves may convey exaggerations unless the person preparing the charts uses as much care as he would ordinarily use to avoid exaggeration if presenting his material by written or spoken words. Most authors would greatly resent it if they were told that their writings contained great exaggerations, yet many of these same authors permit their work to be illustrated with charts which are so arranged as to cause an erroneous interpretation. If authors and editors will inspect their charts as carefully as they revise their written matter, we shall have, in a very short time, a standard of reliability in charts and illustrations just as high as now found in the average printed page.

Fig. 249 shows an interesting application of the use of charts to corporation reports. The back page of the annual report of the American Telephone and Telegraph Company has the proportions seen in Fig. 249. As a report to stockholders is intended to be as optimistic as possible within the limits of truthfulness, there can scarcely be any criticism that the chart was so made that the growth in business was shown on the long direction of the page instead of on the short dimension of the page. The chart in Fig. 249 is simple to understand, and probably very few stockholders would have any difficulty in making a fairly accurate interpretation. For the annual report of a corporation, it is likely that the vertical-bar method of Fig. 249 is preferable, from an advertising standpoint, to a smooth curve like that shown in Fig. 250.

One special point relating to Fig. 249 is worthy of mention. At the bottom of the chart will be noticed the statement that the figures recorded are those of "January 1st of each year". This statement may lead to an erroneous conclusion on the part of the reader, for he may feel that the difference in height between the bar marked 1911 and that for 1912 shows the number of telephones installed during 1912, when, in reality, it shows the number of telephones installed during 1911, since the bars represent the number of 'phones installed to the first of January of each year. If the statement at the bottom of the chart had been made "December 31st of each year" there would be no danger of misinterpretation. If the statement were made for December 31 it would, of course, be necessary to change the numbers at the bottom